In today's mobile information technology environment (e.g., computing or consumer electronics environment), individuals need to guard their privacy against information thieves, hackers, and even just the curious snoop passing by. No longer are address books left at home, or company secrets stored in a drawer at the office; they are carried with the individual as they move from home to work and to all points in-between. Various methods, from file level encryption to power-on passwords, have been employed to secure documents stored on laptop computers. Little is available, however, to protect the mobile user from visual “eavesdropping.” Oftentimes employees find themselves checking e-mail or working in common areas such as airports or coffee shops. In these areas, passers-by or people at the next table may have a clear view of an employee's screen. Depending on various factors such as available light and the angle of view, an unprotected laptop screen may be readable, unbeknownst to the employee, from the side or from over her shoulder, even up to several feet away.
Companies such as 3M sell physical filters that are placed over a computer screen to prevent unwanted viewing. These screens filter out light that is emanating at an angle and only allow out light that is emanating perpendicular to the plane of the screen. The 3M screen in particular utilizes a technology similar to venetian blinds to prevent errant light from escaping at an undesired angle. Therefore, the light representing what is on the screen does not emit at a non-perpendicular angle and is not easily viewed from the side. While this helps prevent others from viewing screen content off-center, it does not solve the problem of unintended viewing from a direct orientation at a distance. Physical screens also require the employee to lug around another piece of hardware and place the onus of implementing security on the user. If the employee finds the device cumbersome or clumsy, the likelihood that it will be used, and used consistently, is diminished.
Applications such as WinAmp and Actual Transparent Windows by Actual Tools utilize transparent application window functionality to allow a user to view applications beneath the window of the topmost application window.